Analog arithmetic circuits are capable of performing high-speed arithmetic operations, but have problems in terms of the stability, accuracy, and program portability. Known circuits capable of digital computing include microprocessors, digital signal processors (DSP), and digital differential analyzers (DDA), all of which are programmable. The microprocessors and DSP, however, are of serial processing type based on von Neumann computers, in which software or programs intervene in the process of arithmetic operations, thus putting a limit to the operation speed. DDA is also of serial processing type, and there is a limit to the operation speed. Digital circuits according to the present invention as described below are programmable only in terms of function setting, and the process of arithmetic operations does not involve serial processing according to software or programs, thus enabling the circuits to achieve high-speed arithmetic operations.